Maths : Basic Numeracy

Q 87 / 370

UPSC CSE Prelims 2024

325 + 227 is divisible by

EXPLANATION

Correct Option (C)

The given expression is 325+227.

  • First, express 32 as a power of 2: 32=25.
  • Substitute this into the expression: (25)5+227.
  • Apply the exponent rule (am)n=amn: 225+227.
  • Factor out the common term 225: 225(1+22).
  • Simplify the term in the parenthesis: 225(1+4)=225×5.
  • To demonstrate divisibility by 10, rewrite 225 as 224×21: 224×2×5.
  • This simplifies to 224×10.

Since the expression can be written as 224×10, it is a multiple of 10 and therefore divisible by 10.

Incorrect Options:

The simplified form of the expression is 225×5. This product consists solely of prime factors 2 and 5.

  • Option A (3): The prime factorization of the expression does not include 3. Therefore, the expression is not divisible by 3.
  • Option B (7): The prime factorization of the expression does not include 7. Therefore, the expression is not divisible by 7.
  • Option D (11): The prime factorization of the expression does not include 11. Therefore, the expression is not divisible by 11.